Hello everybody,
I was reading that the suitable voltage for the B1 buffer preamp from Nelson Pass is between 18V and 24V.
I'm wondering if I'll have catastrophic results if I power it with only +15V ...?

I have run mine with a single nine volt battery as an experiment, no catastrophe. I do run it at 18 volts, though, because that's what papa said to do. Here is a picture of the build, notice the empty Guiness and dinner in the crockpot. (This construction method is not recommended if your spouse is home).